This invention relates to pneumatic tires. More particularly, this invention relates to pneumatic tires capable of being used in the uninflated condition.
Various tire constructions have been suggested which are capable of being used in the uninflated condition. One approach taken is to increase the sidewall stiffness so that the tire can support the vehicle by itself. These tires are generally stiffened by simple thickening the sidewall members by a substantial amount in relation to its normal thickness. Other tires have been stiffened by the placement of an annular sidewall reinforcing means comprising essentially an elastomeric material molded or adhered to the internal sidewall region and having a substantially uniform thickness throughout. For example, as illustrated in U.S. Pat. Nos. 3,911,987; 3,935,892; 3,954,131 and 3,964,532. These tires have a weight disadvantage because of the high amount of rubber in the shoulder area which introduces high centrifugal forces and tends to reduce the durability of the tire. Further, the increased amount of rubber in the sidewall increases the amount of heat generated during use, which becomes even more important when the tire is used in the uninflated condition to the point that the tire may prematurely fail.
British Pat. No. 1,471,883 discloses a pneumatic tire having corrugations formed in the sidewall of the tire. This patent states that the corrugations are preferably formed on the exterior surface of the tire, the interior surface of the sidewall remaining generally plain. The corrugations are described as extending from a point above the rim flange contacting portion of the tire bead to the shoulder of the tire. This patent does not disclose the manner in which the corrugations should be placed on the interior sidewall of the tire.